(1) Field of the Invention
This invention concerns a magnetic head and, more specifically, it relates to the material for a magnetic core made of permalloy for use therewith.
(2) Description of the Prior Art
Permalloy (nickel-iron alloy) has a high magnetic permeability and can be worked with ease such as by rolling, punching or the like and is available at a low cost as well. However, since permalloy is not highly abrasion resistant, it can not provide a sufficient working life to magnetic heads when used as the core material therefor.
In order to obtain a magnetic core of a high hardness in order to overcome the foregoing defect, a nickel-iron alloy incorporated with tantalum within a range of 3.1-23.0% by weight has been proposed.
The inventors of this application have studied the effect of adding tantalum and, as the result, have found that although the hardness (Vickers hardness) of the alloy is increased approximately in proportion to the amount of tantalum added, the hardness of the alloy is not always correlated with the amount of abrasion of the magnetic core caused by frictional contact with, for example, a magnetic tape, and further that the magnetic property of the core such as the saturation magnetic flux density is undesirably reduced as the amount of tantalum added thereto increases.